Battle of Xu Province

The Battle of Xu Province occurred from 193 to 194 AD when the Yan Province warlord Cao Cao invaded Xu Province to avenge his father Cao Song's murder at the hands of Xu Province's governor Tao Qian. While Cao Cao was unable to conquer Xu Province from Tao Qian, he was able to capture a number of towns and punish the civilian populace.

Background
After conquering Yan Province from the Yellow Turbans in 192 AD, Cao Cao became the province's new ruler, incorporating 300,000 captured Yellow Turbans into his own forces as the "Qingzhou Army". Cao Cao then sent for his father Cao Song to join him in Yanzhou, and Cao Song, 40 family members, and 100 servants dragging many carts departed from Langye to join him. Xu Province governor Tao Qian was friendly to the family, entertaining them with feasts for two days before sending his general Zhang Kai and 500 special escorts to guard the family as they headed to Yan Province. However, Zhang Kai - a former Yellow Turban bandit - instead decided to loot the family and escape into the mountains, and they murdered Cao Song and his brother at an old temple and fled south of the River Huai with their loot. Cao Cao swore vengeance against Xu Province as a result, and he left Xun Yu and Cheng Yu with 30,000 troops in Juancheng, Fanxia, and Dongjun as he set forth with the remainder of his army (led by Xiahou Dun, Yu Jin, and Dian Wei) to slaughter the inhabitants of every captured city in Xu Province.

Invasion
Cao Cao's invasion force marched into Xu Province, and Tao Qian's ally Bian Rang, Governor of Jiujang attempted to come to his ally's aid with 5,000 troops; Xiahou Dun stopped and killed Bian Rang while still on the march. Chen Gong failed to convince Cao Cao of Tao Qian's innocence regarding Cao Song's death, and Cao Cao's armies laid waste to Xu Province, slew the people, and desecrated their cemeteries. Tao Qian's strategist Mi Zhu headed to Beihai to ask Governor Kong Rong for help, while Chen Deng headed to ask Tian Kai of Qing Province for help. After defeating the Yellow Turbans, Kong Rong sent his general Liu Bei to assist Tao Qian, as he saw Cao Cao as abusing his strength and injuring the people. Liu Bei's troops marched in front, while Zhao Yun's borrowed troops from Gongsun Zan formed the rear. Liu Bei arrived in Xuzhou and was given the seal of Protector of Xuzhou by Tao Qian, who sought for Liu Bei to take over once he had died; he saw Liu Bei as a benevolent ruler. Cao Cao soon learned both of Liu Bei's arrival and of Lu Bu's concurrent attack on Yan Province, where he had defeated Xiahou Dun. Cao Cao sent Xiahou Yuan to Yan Province to deal with Lu Bu's threat there, but he was too late; Lu Bu and his army marched into Xu Province, intending on finishing off Cao Cao on Zhang Miao's orders. Cao Cao's bodyguard Xu Chu was able to defeat Lu Bu's lover Diaochan, Lu Bu's general Zhang Liao, and then Lu Bu himself in battle, and Lu Bu's army proceeded to retreat from Xu Province in defeat. Cao Cao's army then focused on attacking Tao Qian's army, and Xu Chu used a captured catapult to destroy Xuzhou's gates. Tao Qian was then defeated by Cao Cao's forces, but Liu Bei was ultimately able to convince Cao Cao to make peace with Tao Qian and instead focus on defeating Lu Bu, who still threatened Yan Province. Cao Cao's army then returned to Yanzhou, and, when Tao Qian died in 194 AD, Liu Bei succeeded him as ruler of Xu Province.